At the heart of the modern railway network is the “points operating equipment” (POE). These are devices that facilitate the seamless flow of both passenger and freight trains between interconnecting railway tracks. These systems spend their life exposed to the harshest of environments such as extremes of temperature, driving rain, high humidity, and lightning strikes, not to mention the constant exposure to electromagnetic interference (EMI) from high voltage overhead power supply lines.
Moog designed a special robust brushless servomotor and drive for the hydraulic power units placed alongside rail tracks in “Points Operating Equipment.” After 2 years of in-field use it has proved to be 100% reliable with no failures.
By far the largest percentage of all POE are powered by small dedicated hydraulic power units (HPU) located directly alongside the track. In recent years there has been a move from within the rail industry to convert the electric motor used in these HPUs from a brushed motor to a brushless servomotor in an attempt to eliminate reliability issues from brush and commutator wear and the problems associated with carbon debris from the brushes falling through the motor windings into the bearings and resulting in catastrophic failure of the motor. Many brands of COTS (commercial off the shelf) brushless motors have been trialled in this demanding application but none have survived beyond a few months.
Queensland Rail Partners with Moog
Queensland Rail Ltd is Australia’s largest passenger, freight and coal rail transporter. They have over 60 million passenger movements per year with a rail network that spans more than 10,000 km’s. After a long history of field failures with both the original brushed motors and also the new COTS brushless motors, Queensland Rail approached Moog in Australia to develop an alternative servomotor and drive that would withstand the rigors of this environment whilst providing a robust and field proven solution.
Our major challenge came in designing a solution that would survive two serious threats to the drive electronics:
- Lightning transients that induce thousands of amps into the drive
- Traction fault currents from the high voltage overhead power supply lines that induce many hundreds of volts into the drive.
The Moog brushless motor is designed for both use in new points changing HPU’s and also as a ‘drop-in’ for retrofit into existing HPU’s. It provides a fully integrated solution that can be fitted by field maintenance staff within minutes.
The engineering team at Moog in Australia accepted the challenge and built 10 prototype units that were field tested throughout the Queensland Rail network, located at both metropolitan and regional locations that experienced both the highest volumes of rail traffic and also the most extreme climatic conditions.
After 2 years of in-field use, all 10 prototype motors proved to be 100% reliable, with no failures experienced. Not only that, but in many cases the Moog servomotor was located directly alongside groups of POE where the COTS motors continued to fail. As a result of these exhaustive field tests Queensland Rail has endorsed the Moog servomotor and has subsequently issued a Full Signalling Type Certificate approving its use. This is a level of accreditation that is recognized within the international rail community.
Moog in Australia is now in the process of supplying servomotors in production quantities to Queensland Rail in support of an active retrofit program where existing motors are being replaced over a number of years with the Moog solution.
The Moog motor is designed as a ‘drop-in’ replacement for existing motors and can be fitted by field maintenance staff within a matter of minutes. It can also be supplied with a customized HPU top cover, designed to accommodate the slightly larger Moog motor assembly.
This program demonstrates two elements of what enables Moog to provide superior motion control solutions.
- Moog’s core skill is in designing and building robust motion solutions for the most extreme of conditions.
- We have access to best-in-class components in house. In this case Moog in India manufactured the base Fastact G 400 Series Brushless Servomotor, Moog in Germany integrated the onboard electronics and Moog in Australia designed and added the customized protection circuitry.
Moog has already been approached by a number of local and international companies who specialize in rail trackside equipment and see the Moog motor as providing a robust solution to what is clearly a global problem.
Author
Peter Clements has been with Moog Australia for 8 years in the capacity of Queensland and Western Australia State Manager. Prior to joining Moog he worked extensively within the Hydraulics industry. Peter studied Mechanical Engineering at the Leicester Polytechnic, Leicester UK and also completed a technical apprenticeship within the UK machine tools industry.